05.33: LTB resistance of rolled I‐section beams: FEM verification of Eurocode's buckling curve formulation

Abstract

This paper attempts to verify the Eurocode's buckling resistance criteria in case of rolled I-and Hsections in monoaxial bending about their major axis using finite element simulations and two imperfection modelling techniques, namely a) using the equivalent geometric imperfection concept in which the effect of material and geometrical imperfections is represented by an equivalent minor axis bow amplitude and the lowest eigenmode imperfection profile, and b) the separate inclusion of material and geometrical imperfections. In the latter approach, material imperfections are based on the standard rolled residual stress patterns consisting of compression/tension peak values dependent upon the h/b ratio. Moreover, the geometric imperfections are included as the tolerance limit of steel I-section rolled products. Common and higher grades of steel products are considered. The finite element shell model is utilized and built within the ABAQUS software. The Eurocode's resistance criteria are verified by using the results of FEM simulations. An impact of the moment gradient on the member buckling resistance as well as the plateau limit evaluation and the resistance increase as a result of large twist rotations accounted for are assessed. Remarks in relation to analytical formulations presented in Eurocode 3 are drawn.

Buckling Resistance Criteria of Prismatic Beams Under Biaxial Moment Gradient

“…In Giżejowski et al (2017a), it has been concluded that Eurocode's LTB curves coincide with the resistance curves obtained from the general interaction equations for biaxial bending and compression when N Ed = M z,Ed = 0. Furthermore, it was indicated that there were substantial differences in the resistance curves derived from the so- Fig.…”

“…Detailed results are presented elsewhere, and only a brief summary is presented here. Figure 7 reproduces the finite element results presented in Giżejowski et al (2017a) for the S 355 steel grade and referring to a uniform moment; the discrete diamond points are from the finite element simulation based on Approach 1 for imperfection modelling, and the triangular points indicated by GM-EC 3 are based on Eurocode's socalled General Method with equivalent geometric imperfection modelling (Approach 2 according to Sect. 3.3).…”

“…In this section, in the Eurocode prediction of biaxial bending resistance, the values of χ LT,mod The finite element models were previously validated; for many cases, these validations were presented in Giżejowski et al (2016cGiżejowski et al ( , d, 2017a and Gizejowski and Stachura (2017). This paper is a continuation of long-term research and is part of the current research of Papp (2016).…”

05.27: Resistance of mono‐axially bent beams of welded I‐sections: FEM verification of Eurocode's buckling curve formulation

“…[11]) that the section resistance is for the moment gradient cases achieved for a greater value than 0.2. It supports the observations made for rolled I-section (cf.…”

“…The boundary conditions are modelled in the way analogous to that summarized in [11]. Since the end sections are composed of three sub-contours, the application of major axis end moments may be done directly at the web sub-contour gravity centre.…”